The A-pillars on an automotive vehicle are the structural members of an automotive frame positioned between the windshield and the front doors. The A-pillars support the roof structure as well and, therefore, must provide substantial support in rollover events. At the same time, the A-pillar lies within the sight lines of the operator and needs to have a minimal profile to allow the operator to maintain binocular vision with respect to the A-pillar. Thus, the designers of automobiles are faced with conflicting requirements with respect to the design of the A-pillars. To provide a strong structural member, the A-pillar needs to have a maximum cross-sectional configuration, yet maintain a minimal cross-section for vision purposes.
To achieve maximum cross-section of a tubular inner member for an A-pillar body structure, while maintaining acceptable binocular vision standards, a traditional flange formation and welding is restrictive. The flanges provide for a sealing relationship with respect to both the windshield and the front door that are supported on the A-pillars. Typically, the elastomeric seals for both the windshield and the adjacent portion of the front doors are mounted on the flanges of the A-pillars. The door opening panel is typically welded on the outside of the A-pillar structure to provide a uniform surface against which the front door can close.
The conventional A-pillar structure is reflected in FIG. 2, which is a cross-sectional view of the A-pillar corresponding to lines A-A of FIG. 1. The A-pillar 10 is formed of a shaped inner member 12 that is formed with opposing vertically extending flanges. A reinforcement member 15 having mating flanges is welded at the flanges to the outer side of the inner member 12 to form a generally vertically extending beam 10. The door opening panel 16 is also formed with mating flanges that are welded to the flanges of the reinforcement member 15. The door opening panel 16 provides a uniform surface for support of the windshield 17 supported in an elastomeric seal 18 against the welded flange 13, while the front door (not shown) closes against a seal (not shown) typically mounted on the opposing welded flange 14. The distance from the lateral ends of the opposing welded flanges 13, 14 defines the arc of seven and a half degrees, or less, relative to the position of the operator of the vehicle.
It would be desirable to provide an A-pillar configuration that has an increased cross-section and greater tube size to provide a greater measure of strength for the A-pillar, while maintaining dimensional standards for binocular vision by the operator of the vehicle.